Talaporfin Sodium–Mediated Photodynamic Therapy Alone and in Combination with Pulsed Dye Laser on Cutaneous Vasculature  Kristen M. Kelly, Wesley J. Moy, Austin J. Moy, Ben S. Lertsakdadet, Justin J. Moy, Elaine Nguyen, Ashley Nguyen, Kathryn E. Osann, Bernard Choi  Journal of Investigative Dermatology  Volume 135, Issue 1, Pages 302-304 (January 2015) DOI: 10.1038/jid.2014.304 Copyright © 2015 The Society for Investigative Dermatology, Inc Terms and Conditions

Figure 1 The combination of talaporfin sodium (TS)-mediated photodynamic therapy (PDT) and pulsed dye laser (PDL) irradiation leads to a significant reduction in the characteristic PDT radiant exposure required to achieve persistent vascular shutdown. We first determined the characteristic radiant exposures associated with persistent vascular shutdown following 595-nm PDL irradiation. We performed PDL on the epidermal side of window chambers and imaged blood flow using laser speckle imaging (LSI). We assessed persistent vascular shutdown on day 7. We assigned a “0” score if some evidence of blood flow was present, and a “1” score if flow was no longer evident. We used dose–response analysis to calculate a characteristic radiant exposure (RE50/7) at which 50% of irradiated window chambers are expected to have vascular shutdown on day 7. (a–c) Representative LSI data associated with 595-nm PDL irradiation, in which persistent vascular shutdown was not (a, b) and was (c) achieved, using radiant exposures of (a) 4, (b) 6, and (c) 10 J cm−2, respectively. (d) On the basis of data from 19 experiments, we identified an RE50/7 of 7.1 J cm−2 for PDL irradiation. We then studied the combination of TS-mediated PDT and PDL irradiation. In this set of experiments, we used PDT (20–60 J cm−2) and PDL radiant exposures (4–6 J cm−2) that were below the RE50/7 values of 85 J cm−2 (Moy et al., 2012) and 7.1 J cm−2 (d), respectively. (e) Representative maps of blood flow that demonstrate persistent vascular shutdown at day 7. In this specific example, we applied PDT (60 J cm−2) followed by PDL (6 J cm−2). This combination resulted in marked acute vascular shutdown, which persisted through day 7. (f) On the basis of data from 30 experiments, we determined that the characteristic radiant exposure required to achieve persistent vascular shutdown decreased from 85 J cm−2 with PDT alone to 45 J cm−2 for the combined PDT+PDL protocol. Bar=2 mm. Journal of Investigative Dermatology 2015 135, 302-304DOI: (10.1038/jid.2014.304) Copyright © 2015 The Society for Investigative Dermatology, Inc Terms and Conditions